[rotorwrench]

If I had a bar, I would likely try it at some point. A really good boring machine will keep better accuracy but it's been done with a boring bar many times I'm certain. If you have a junk block you might experiment some first.

A lot depends on the type of sleeve and thickness of wall needed. I have tools to drive the sleeves in the Ford tractors. They have the same bore as a flathead V8 but they are made for sleeves. Freezing the sleeve with dry ice can help since they usually just drop in with a .0015" to .002" interference fit but it also depends on whether the sleeve will have to hold coolant too (wet sleeve). Some surfaces need to remain clean for sealant if that's the case and freezing will lead to condense on the part during assembly. A wet sleeve would only be required if a person bores through the cylinder wall. Anaerobic sealant or epoxy adhesive like JB Weld or Scotch weld can be used for sealant but I don't know what you have in the UK. Epoxy is good to hold the deck a bit firmer on a flathead.

Sleeves can require a step being left at the bottom of the bore if there is still material there and there usually always is unless it has a broken spot down there. This will keep the sleeve from moving down any further. A person has to take care not to break it when driving the a sleeve the last bit if driving it is necessary. A hard wood block and a big hammer will seat a sleeve as far as it can go. A person can install it down to the last inch & a half or so by the dry ice method then let it equalize and clean it real well before sealing the top & bottom then drive it the rest of the way.

You only need to sleeve the one cylinder unless the cylinder walls are getting pretty thin on the others. You can even bore a sleeve a bit it it's not a real thin one.